Pedestrian Traffic Engineering PrinciplesHow the Mayor’s Path Through the Bosque Will Run Pedestrians Out, Increase the Crime Rate, and Complete the Ecocide We Started

A Surfaced Graded Trail Induces Travel

Traffic engineering formulas say for every 10 feet you widen a highway, you increase traffic by 3.3 percent.[i]

The Paseo del Bosque is a bicycle trail adjacent to the bosque. The mayor’s proposed 10-foot-wide graded and surfaced trail within the bosque falls under this traffic engineering rubric.

The city says 780 cyclists a day pass under I40 on the Paseo del Bosque. Three point three per cent of that is nearly 25 cyclists a day. So the minimum induced travel on the mayor’s proposed path would be 25 cyclists a day. Given a 12 hour day, that’s one cyclist traveling through the bosque every half hour.

A much more likely scenario is that half of the Paseo del Bosque cyclist traffic will use the mayor’s proposed path, for 390 cyclists a day. Given a 12-hour day, that works out to 32.5 cyclists per hour traveling through the bosque, about one every two minutes.

A reasonable scenario would be that the path doubles cyclist traffic adjacent to and within the bosque, such that 780 cyclists a day use the Paseo and 780 a day also use the inner bosque trail. Given a 12-hour day, that works out to 65 cyclists traveling through the bosque per hour, or just over one cyclist per minute.

2. Cyclists Run Pedestrians Out, No Pedestrians Increases Crime

The proposed 10-foot wide path, when shared, would be safe neither for pedestrians or cyclists.

Albuquerque has done a survey of conflicts between users of its many multi-use paths. This is what the then trails coordinator had to say on the international pedestrian engineering listserv, Pednet:

Here in Albuquerque, New Mexico we have over 80 miles of paved multi-use trails. The weekends are the worst times for user conflicts due to the varying speeds of users,i.e. rollerblaers and bicyclists vs. walkers and runners. The only solution is either separated paths or wider paths, say 14 feet. Otherwise it will forever be a problem.

We recently completed trail counts and surveys. 368 surveys were collected and many of the comments were “please make the trail wider and smoother”, and this was from rollerbladers and bicyclists. Most walkers and runners would actually prefer an unpaved surface, since it is easier on your hips, knees, and ankles vs. walking or running on concrete or asphalt.

This is obviously not a full blown study but I can assure you that the data

we’ve collected here over the past two weekends is indicative of the needs and conflicts which exist nationwide on trails whether they be in urban or more off-road/wilderness areas.

City transportation planner Julie Luna confirms this is the only study Albuquerque has made of conflicts between users of trails.

“Shy space” or “shy distance” is a term used by pedestrian traffic engineers to calculate safe widths for sidewalks, trails, and bicycle lanes. One fast-moving pedestrian such as a runner requires three feet of shy space. Give that runner a dog, who also requires three feet of shy space, and six feet of shy space are required for just two pedestrians.

On a 10-foot-wide trail such as the one the mayor proposes, that leaves four feet of shy space for one cyclist to pass the slower-moving pedestrians. Best practice traffic engineering principles for cyclists recommend six to eight feet of shy space for each one. Any trail through the bosque that would safely allow both cyclists and pedestrians to use it would need to be 12 feet wide at a minimum, or 14 feet wide as the Albuquerque trails coordinator suggested.

Crime increases as pedestrians decrease. Out of the line of sight of motorists, a cyclist-only bosque would harbor increased assaults under the well-documented public safety rubrics of “eyes on the street”. [iii]

A 14-foot-wide trail through the bosque would induce even more cyclist travel, decrease pedestrian travel, and increase crime.

3. Animals and Birds Flee Increased Human Contact

These statistics can best be calculated by the many professional naturalists who oppose the mayor’s path. Gale Garber of Hawks Aloft Inc. has scientifically surveyed bird life in the Rio Rancho bosque since so-called invasive plants which provide nesting habitat were removed, and a crusher fine trail installed. The reduction from over 700 summer birds per 100 acres to under 200 in just eight years cannot be accounted for by drought alone.

The minimum induced travel of one cyclist per half hour twelve hours a day – much less the maximum of one cyclist every minute – would have a permanent damaging effect on the safe nesting habitat of birds, mammals and reptiles in the bosque.

[iii]For “eyes on the street”, “shy space” and “barrier effect” outcomes, see the most recent best practices guide recommended by the experts at the international pedestrian traffic engineering listserv, Pednet: Pedestrian and Bicycle Planning: A Guide to Best Practices, Victoria (B.C.) Transport Policy Institute. Their director, Todd Litman, is thought by senior pedestrian traffic analysts to be among the most solid analysts now at work.

The mayor’s vision for the bosque from the first plan through this last one, of which the main feature is still the 10-foot wide surfaced trail, has always had a peculiar dissonance with the nature preserve character of the site. An eyewitness to a discussion with Hizzoner told me the mayor’s vision is pretty much based on his desire to ride his mountain bike through the bosque.

A battle 10 years ago in Washington, D.C. to keep the city, backed by the powerful Washington Area Bicyclists Association, from stripping a 10-foot wide asphalt “trail” down the middle of a long and skinny neighborhood park taught me cyclists are the most entitled of athletes. And the least interested in, and the least scrupulous in protecting, the slow-moving amenities of pedestrians. It may be different in the land of enchantment, but in Washington, D.C. cyclists are the highway lobby dressed in green clothing.

Without going into the truly ferocious war stories of the battle between the dogs and the toddlers and the runners and the baseball players and jungle gym climbers and basketball players and tot lot occupants whose right to the public space they already occupied in the park carried no sway with the city or the cyclists, I have started to think about mountain bikers.

Only about 3% of all Americans participate in mountain biking, as opposed to the far greater number of pedestrian athletes — 12% hiking and 18.5% trail running, according to the Outdoor Foundation 2013 Outdoor Participation Report. Outdoor recreation is a man’s world; women’s participation peaks early in life, with 60% of six-year-olds playing outdoors. The percentage of women playing outdoors is all downhill from there, coming to rest with under 20% of women over 66 playing outdoors — as compared to twice as many men — 40% of men 66 and over.

Mountain biking is a Hispanic and Caucasian man’s world. Here are the Outdoor Foundation demographics by race of mountain bikers and other outdoor recreationists:

Hispanics are the biggest percentage of people who mountain bike (17%), with Caucasians at 16%, Asian and Pacific Islanders (of whom the 2010 census counts about 600 in Albuquerque) at 14%, and African Americans at 11%. About three percent of children do mountain biking, and 2% BMX (competitive dirt trail racing).

A 10-foot wide paved trail through the bosque would induce travel by cyclists at rates pedestrian traffic engineers have scientific formulas to calculate.

These cyclists would, as a matter of well-documented fact, chase pedestrians away. What would be left for outdoor recreation in the bosque is a path it costs $743, at a minimum, to access and use.

And what is the average income of the Hispanic communities closest to the part of the inner city bosque the mayor wants to close to everyone who doesn’t have $743?

In Barelas, the median per capita income is $16,118 a year. Households earn $29,194.

In Atrisco, the per capita income is $16,685 and household income is $43,052.

The Outdoor Foundation reports 35% of outdoor recreants — and remember, mountain cyclists are men — are cutting back on non-essential expenses in 2013. No one has done the statistical breakdown for Hispanics and their beloved mountain biking. But the user surveys show that everyone who recreates out of doors lists a pedestrian activity as their first preference.

It’s not hard to conclude that the mayor’s vision for the bosque, the centerpiece of which remains a 10-foot-wide surfaced trail, would essentially close the bosque to most of the people who live near it and wish to use it. The imposition of a plan privileging men on bicycles, and dis-empowering pedestrians — the majority of users of outdoor recreation — has a political theory component. It is a disturbing unilateral exclusionary move via landscape architecture. It fits into the centuries-long history of the privatization of public space by minority interests. The Spanish broke the Indians’ backs and privatized public land and water by making them dig the first acequia. The river hasn’t been the same since.

This is an excerpt from a report I wrote for another park 10 years ago. The dates but not the principles have changed, and some bosque-specific information has been added.

I. Multi-Use Trails

“Multi-use trail” is, in practice, a bicycle commuter highway that joggers and walkers shun. The asphalt surface injures joggers’ ankles, knees, and hips. Given a choice, they prefer to run on the earth alongside existing multi-use trails, according to the only recent survey on conflicts between users of multi-use trails, done in Albuquerque, N. M.[i]

Two thirds of walkers on multi-use trails fear cyclists, according to a federal report on conflicts between users of multi-use trails. Bicycle traffic volume on weekends appears to outpace rush hour traffic all day, thus mimicking weekend auto traffic statistics.[ii] It also corroborates the Albuquerque survey finding that user conflict on multi-use trails worsens on weekends.

In the 10 years since the foundation of multi-use trails, there have been only two studies on conflicts between users, according to the 300-plus pedestrian traffic experts on the international e-mail listserv, Pednet.

The first study of conflicts between multi-use trail users was commissioned by the Department of Transportation when the funds were set aside nine years ago.[iii] User conflict was seen as the number one problem with multi-use trails. This prediction has proved correct. Recently, the city of Albuquerque, N.M. tallied the conflicts between the 368 respondents to a survey of users of their multi-use trails. The city trails coordinator concluded, “The only solution is either separated paths or wider paths, say 14 feet. Otherwise it will forever be a problem.”

Lacking other precedent, four well-established principles of urban planning and traffic engineering are useful to inform speculation on the future of a multi-use trail.

The first is the certainty that widening induces travel. Senior researchers of the National Academy of Sciences (U.S. government academics, not the highway lobby, nor greens) have authoritatively concluded that every 10 per cent increase in the width of a highway leads directly to a 3.3 per cent increase in the number of vehicles traveling upon it.[iv] This is a revolution in thinking previously formed by the highway lobby credo, “ease traffic congestion” by building more roads and widening extant ones. What actually happens is that gridlock is not eased, simply widened.

One career environmentalist and long-term observer of the bosque estimates 3 to 5 people an hour currently walk the main bosque path on a summer day.

According to the city, “an average of 780 bike riders per day pass under I-40 on the Paseo del Bosque”. Given a 12-hour day, that’s 65 bicycle riders an hour, more than one a minute. If the proposed bosque path is connected to the existing Paseo del Bosque trail, pedestrian traffic engineers calculating the environmental impact of a 10-foot-wide surfaced multi-use trail through the bosque would need to take this high volume of use on a parallel path into consideration. As far as I know, no bosque path usage or environmental impact study has been done. But these figures, from 3 to 5 an hour to one a minute, suggest and can be used as ballpark parameters for estimating induced traffic on the proposed trail and its impact on pedestrians, including bosque fauna attempting to cross the trail at twilight, or those inclined to depart high levels of human activity.

Immanent calls by cyclists and bladers for future widening of what is officially designated “multi-use” will almost certainly ensue, as the Albuquerque survey suggests. Conflicts between users are intractable, as the federal report foresaw before there were any trails or users, and as the Albuquerque survey corroborates nearly a decade later.

Second,[v] an urban planning concept known as “eyes on the street” comes into play. A Jane Jacobs concept, the idea is that crime decreases as the number of pedestrians on foot increases. [I wrote this whole document about a proposed path through a neighborhood park in Washington, D.C.. I’m leaving this part in, because while specific to the D.C. site, it also explains in detail what will happen in the Bosque when pedestrians are chased out:

[The Rock Creek Park bicycle commuter path usage survey conducted by the Happy Trails Caucus shows walkers shun the bikeway. The bikeway which crosses west of the creek, and passes under the P Street bridge has sheltered repeated attacks. The first series of assaults were by an ice-pick-wielding bicycle thief (1994). The second series were by a rapist intent on assaulting lone female joggers (1996). This crime zone was created – according to this rubric of eyes on the street – due to the fact that walkers shun it, and that it is out of the line of sight of motorists. Thus, the establishment of a multi-use trail in Rose Park would possibly create a crime zone by eliminating walkers from the mix, as they have been eliminated from the mix on the Rock Creek Park bicycle commuter path, for which a link is sought to Rose Park.

[If someone knows a similar crime zone on Albuquerque’s cyclist trails that demonstrably, with newspaper clips of the crimes, has become dangerous because pedestrians have been forced out of the area by cyclists, please do the research and make the point at the public meetings Sept. 4 and Sept. 18 on the mayor’s plan for the bosque. If you could give me your sources of info and corroboration, in a formal bibliography, I’d be delighted to include it here with a credit to you.

[In ABQ the Plan, city public safety authorities are quoted (p. 32) on this principle, saying an increase of visitors to the park will make it safer. They seem not to have taken into account that an increase of cyclist visitors, who are not considered eyes on the street, will run off all other law-abiding users of the proposed trail.]

Third, traffic engineers calculate that each pedestrian on foot requires only 1.5 feet of what they term “shy space”. As speed increases, so does the amount of shy space required. Thus, two pedestrians walking very quickly side by side would each require 3 feet of shy space, for a total of 6 feet of shy space. A sidewalk of 6 feet wide would thus be recommended, under the best practices rubric, to accommodate just two fast-moving walkers. A multi-use trail would add even faster-moving cyclists and bladers to this mix. The proposed bosque multi-use trail is 10 feet wide. Given just two fast-moving walkers abreast, that leaves four feet of shy space for cyclists and bladers. Cyclists are usually calculated as needing six to eight feet of shy space apiece. No reasonable plan would increase bicycle traffic while expecting cyclists and bladers to confine themselves to four feet of shy space.

The fourth possible outcome for a multi-use path in the bosque is known to pedestrian traffic engineers as the “barrier effect.” As with Robert Moses’ Bronx Expressway, a broad asphalt surface with induced traffic traveling upon it prevents pedestrians from crossing to the other side. The barrier effect creates dead space on the side of the highway to which people do not cross. Thus, a multi-use path could halve the space people use, could create a dead zone in the half of the park to which no one wishes to cross. In the bosque, amphibians like the soft-shell and painted turtles who live in the water and emerge to lay eggs on land have a low tolerance to lack of cover. A 10-foot paved trail along the river’s edge would prove a barrier to migration for reproduction that the turtles would be unlikely to overcome. According to one long-term scientific observer of the bosque, a 10-foot paved path would create a barrier effect which could drive amphibians from the bosque.

Here in Albuquerque, New Mexico we have over 80 miles of paved multi-use trails. The weekends are the worst times for user conflicts due to the varying speeds of users,i.e. rollerblaers and bicyclists vs. walkers and runners. The only solution is either separated paths or wider paths, say 14 feet. Otherwise it will forever be a problem.

We recently completed trail counts and surveys. 368 surveys were collected and many of the comments were “please make the trail wider and smoother”, and this was from rollerbladers and bicyclists. Most walkers and runners would actually prefer an unpaved surface, since it is easier on your hips, knees, and ankles vs. walking or running on concrete or asphalt.

This is obviously not a full blown study but I can assure you that the data

we’ve collected here over the past two weekends is indicative of the needs and conflicts which exist nationwide on trails whether they be in urban or more off-road/wilderness areas.

That’s a dead link from the original document I wrote 10 years ago. It may refer to this, but I doubt it.

A study of readers of Backpacker magazine found that over two-thirds felt the use of mountain bikes on trails was objectionable (Viehman 1990). Startling other trail users, running others off the trail, being faster and more mechanized, damaging the resources, causing erosion, frightening wildlife, and “just being there” were the biggest concerns (Kulla 1991; Chavez, Winter and Baas 1993). Keller (1990) notes that brightly colored clothes, a high-tech look, and the perception of a technological invasion can all be sources of conflict felt by others toward mountain bikers.

Noland, Robert B., and Lewison L. Lem. Induced Travel: A Review of Recent Literature and the Implications for Transportation and Environmental Policy. Paper to be presented at the European Transport Conference, Sept. 2000. London: click Research, then Current Working Papers. Centre for Transport Studies, Imperial College of Science and Medicine, 2000. http://www.cts.cv.ic.ac.uk/

Noland, Robert B., and William A. Cowart. (August, 2000.) Analysis of Metropolitan Highway Capacity and the Growth in Vehicle Miles of Travel, forthcoming in the Journal of Transportation and Statistics. London: click Research, then Current Working Papers. Centre for Transport Studies, Imperial College of Science and Medicine, 2000.

[v] For “eyes on the street”, “shy space” and “barrier effect” outcomes, see the most recent best practices guide recommended by the experts at Pednet: Pedestrian and Bicycle Planning: A Guide to Best Practices, Victoria (B.C.) Transport Policy Institute. Their director, Todd Litman, is thought by senior pedestrian traffic analysts to be among the most solid analysts now at work.